What is exophthalmos (bulging eyes)?

Exophthalmos is the term used to describe bulging eyes – eyes that protrude out of their normal position. It is also known as proptosis. Very often this can be a sign of a potentially serious underlying medical condition, such as hyperthyroidism.

Generally, protruding eyes are considered bulging if the whites of the eyes are visible between the iris (the coloured part of the eye) and the upper eye lid. Sudden bulging should be treated as an emergency.

Prognosis of exophthalmos

If bulging occurs suddenly, there is a small risk that the optic nerve is compressed by the pressure caused by exophthalmos, and therefore without rapid treatment your sight may be affected.

However, if a symptoms of thyroid disease, exophthalmos can subside with time and treatment. Sometimes corrective surgery will be needed to stop the eyes from bulging permanently.

In some cases of exophthalmos, patients are left with long-term sight problems, such as double vision, but permanent problems are rare.

Symptoms of exophthalmos

Exophthalmos is the bulging outwards of the eyes. If it is a symptom of an underlying condition, you may have other symptoms of this condition.

Medical tests to diagnose exophthalmos

If your eyes begin to bulge, either both or just one, see a doctor. Your doctor will want a full medical history and will conduct a physical exam. Further tests will be carried out to determine the underlying cause of the exophthalmos, including a vision test, a CT scan or MRI and blood tests.

What are the causes of exophthalmos?

The most common cause of exophthalmos is hyperthyroidism (an overactive thyroid gland). This gland is found in the neck and is responsible for releasing hormones that help to control the metabolism. Hence, with hyperthyroidism too much of these hormones are released.

Another common cause of bulging eyes is Grave’s disease, which is an autoimmune disorder that causes hyperthyroidism.

Other causes of exophthalmos include:

• Certain cancers (leukaemia, neuroblastoma, lymphoma)
• Haemangioma (an abnormal collection of blood vessels)
• Injury to the eyes
• Infections to the eye
• Sarcoidosis

Treatments for exophthalmos

Treatment will depend on the underlying cause of your exophthalmos, but can include eye drops, antibiotics or surgery. If hyperthyroidism or Grave’s disease is diagnosed, then you will be treated for these conditions, either with medications, surgery or hormone therapy. If the underlying cause is cancer, then surgery, radiotherapy or chemotherapy will be recommended, however, you will be referred to a cancer specialist at this stage.

Surgery may involve the following:

• Eyelid surgery – to improve the closure and appearance of the eyelids.
• Eye muscle surgery – aligns the eyes and reduces any double vision.
• Orbital decompression surgery – small sections of bone are removed from the eye socket.

Which type of specialist treats exophthalmos?

Depending on the underlying cause, different specialists will treat exophthalmos. However, it will likely be treated by a multi-disciplinary team including ophthalmologists, surgeons, endocrinologists and oncologists.